Library

Notes: The time required for ovarian follicular development in the cyclic hamster was determined by marking follicles with [3H]-thymidine on day 1 of the estrous cycle (day of ovulation) and by following their fate over the next three cycles by autoradiography. A model of follicular development was formulated, based on the total number of follicles and the changing percentage of labelled follicles with time.It was estimated that 20 days elapsed before a preantral follicle with two to three layers of granulosa cells (stage 1) was able to ovulate. Follicles spent eight days in stage 1 and an additional eight days in stage 2 (4-5 granulosa layers). Preantral follicles entering stage 3 (6-7 granulosa layers) and 4 ( 8 layers) on day 1 of the cycle ovulated four days later.Approximately 30 follicles per ovary entered and left stage 1 each cycle, representing a 50% turnover. Of the follicles leaving stage 1, about 50% were transformed into stage 2 follicles; the remaining ones underwent atresia. Stage 2 follicles also had a 50% turnover each cycle. Half of the stage 2 follicles underwent atresia; the remainder developed into stages 3 and 4 follicles Fifty percent of the stages 3 and 4 follicles present on day 1 of the cycle ovulated at the next estrus with the remainder undergoing atresia.

Notes: The histochemistry of lipids, Δ5-3β-, 20α and 17β-hydroxy-steroid dehydrogenases, glucose-6-phosphate and isocitrate dehydrogenases, NADH and NADPH-diaphorases and acid phosphatase has been studied in the ovary of the cyclic hamster. None of the enzymes studied was present in the preantral follicles on day 1 (day of ovulation) or any day of the 4-day cycle. With the development of antral follicles (on day 3) a few fine lipid droplets appeared in the granulosa cells. The theca interna exhibited moderate amounts of NADH-diaphorase, Δ5-3β-HSDH, 17β-HSDH and slight NADPH-diaphorase, G-6-PDH and ICDH, whereas the granulosa cells of antral follicles showed weak Δ5-3β-HSDH, NADH-diaphorase and moderate 17β-HSDH but intense NADPH-diaphorase, G-6-PDH and ICDH activities. All enzyme activities in both theca and granulosa became more pronounced on proestrus (day 4).In the corpora lutea (CL) all the above enzymes were present on day 1 and increased on day 2, followed by a rapid decline on days 3 and 4. Lipids were sparsely represented in CL on days 1 and 2 but showed marked accumulations on days 3 and 4. Likewise, acid phosphatase increased on days 3 and 4. The enzyme 20α-HSDH was not detectable in the CL.The interstitium showed moderate amounts of lipids, Δ5-3β-HSDH and NADH-diaphorase while 17β-HSDH, NADPH-diaphorase, G-6-PDH and ICDH were only weakly present. There were no appreciable changes in the lipid and various enzymes in the interstitium throughout the cycle except for Δ5-3β-HSDH which increased slightly on the afternoon of day 4. Acid phosphatase was not detected in appreciable amounts in the interstitium throughout the cycle.These findings suggest that preantral follicles are unlikely to contribute to steroidogenesis. The antral follicles are the principal source of estrogen, with the granulosa being the major site of synthesis. The interstitium can serve as a major source of progesterone (P) while the theca interna and granulosa cells of antral follicles may form additional sites for P synthesis on the afternoon of day 4. The CL in the hamster are very short-lived and steroidogenesis in them may proceed beyond the synthesis of progesterone. The present findings are correlated with the steroid levels found during the cycle. Appropriate comparisons are also made with the rat ovary.

Notes: To determine the rate of follicular development in long-term hypophysectomized (H) hamsters, single IP injections of 3H-thymidine were given six days after H and autoradiographs were prepared from animals killed on days 6-15. Only follicles in stages 1 (2-3 layers of granulosa cells), 2 (4-5 layers) and 3 (6-7 layers) were present and there were fewer follicles than in intact, cyclic hamsters. The entire population of follicles in stages 1 and 2 was replaced every five to six days in hypophysectomized hamsters, whereas in cyclic hamsters, complete turnover takes eight days (Chiras and Greenwald, '77).Other groups of H hamsters were treated on days 4-6 with either estradiol benzoate (EB  -  10 μg), progesterone (P  -  1 mg) or EB and P and then given 3H-thymidine at 0900 hours of day 6 and killed one hour later. Steroid treatment affected early stages of follicular development: EB stimulated growth of these follicles; P alone had little effect; given with EB, P acted as an antagonist.Other H hamsters were treated with FSH (100 μg), LH (10 μg), FSH + LH, PMS (30 IU) or saline vehicle at 0900 hours six days post-hypophysectomy. They were injected with 3H-thymidine at 2100 hours on day 6 and killed one hour later. LH- and saline-treated animals had approximately the same number of follicles; however, there were no stage-3 follicles in the LH-treated group and the percentage of labelled follicles in stages 1 and 2 was significantly lower after LH treatment. FSH enhanced follicular development and thymidine uptake. Twice as many stage-3 follicles were seen in FSH-treated animals as controls; stage-4 follicles (〉8 layers of granulosa cells) were also encountered after FSH treatment. Labelling Index (LI) and Intensity (L. Int.) for the FSH-treated group were the highest of all treatments. LH antagonized some of the effects of FSH. PMS resulted in follicular growth similar to that achieved by FSH; however, PMS markedly depressed LI and L. Int., which was probably due to the LH-like component of PMS. These results demonstrate that the gonadotropins affect the development of small follicles. FSH stimulates growth; LH depresses follicular growth when administered alone and antagonizes some of the effects of FSH.Hamsters pretreated with EB or P on days 4-6 and then given a single, subcutaneous (SC) injection of FSH at 0900 hours on day 6, were treated with 3H-thymidine at 2100 hours on day 6 to assess the interaction of steroids and FSH. EB pretreatment caused the development of stage-5 follicles (early antral follicles) but did not increase thymidine uptake (measured by LI and L. Int.) in the small follicles above that attained by FSH alone. P pretreatment diminished thymidine uptake in small follicles, but did not reduce their number.These results demonstrate that in the hamster the population of small follicles, i.e., the often misnamed “pituitary-independent” follicles, can be influenced quantitatively and qualitatively by steroids and gonadotropins.

Notes: New thermally stable polyamides were prepared by interfacial polymerization of the title compounds and various aliphatic and aromatic diamines. The polymers were characterized by infrared spectrometry, elemental analysis, and differential scanning calorimetry. The molecular weights of the polymers were estimated by viscosity measurements. The influence of the halogen content on the thermal properties and degree of polymerization of the polymers was studied. One of the polyamides was fractionated to determine the degree of polydispersity.