ISSN:
0002-9106
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
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.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aja.1001520304
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