ISSN:
1573-899X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Production of FSH and LH by the human embryonic pituitary in vitro has been studied during the action of hypothalamic or pineal tissue on the pituitary in 125 fetuses after 17 to 40 weeks of intrauterine development. 2. The pituitary of female fetuses can secrete FSH and LH spontaneously into the medium only between the 19th and 29th week of embryogenesis; the pituitary of the male fetus can secrete only FSH spontaneously into the medium, and only between the 24th and 29th week of development. 3. Factors stimulating FSH secretion by the pituitary are found in the hypothalamus of fetuses of both seses. No sex difference in the level of their activity has been established, but the period during which they are found depends on the sex of the fetus: in female fetuses these factors are found from the 19th to the 29th week, but in male fetuses from the 24th to the 29th week of development. 4. Under experimental conditions in vitro, addition of pineal gland was a factor evoking sex differences in the level of FSH secretion: from female fetuses it stimulates secretion, while pineal gland from male fetuses inhibits it (except, perhaps, for the period between the 24th and 26th weeks of development of the male fetus). 5. In the hypothalamus of fetuses of either sex factors weakly stimulating secretion of LH by the pituitary are found. No sex differences exist in the level of their, activity, but the duration of the period when they are found is as dependent on sex of the fetus as in the case of, FSH. These factors are present in female fetuses from the 19th to the 29th week, and in male fetuses from the 24th to the 29th week of development. 6. Sex differences in the level of LH secretion are due to the appearance of reserpine-sensitive factors, activitly stimulating LH production, in the hypothalamus only of female fetuses, after the 20th week of development.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01125595
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