Changes in hypophyseal luteinizing hormone (LH) content during fetal and early postnatal life, and capacity of fetal and early postnatal pituitaries to synthesize and release LH in vitro.
The developmental pattern of hypophyseal luteinizing hormone (LH) during fetal and early postnatal life, and the capacity of fetal and early postnatal pituitaries to synthesize, release and store LH in the absence of any hypothalamic influence were investigated. Pituitary radioimmunoassayable LH was detectable by fetal day 12; its level remained low up to fetal day 17 and thereafter continued to increase up to postnatal day 2 with sharp rises occurring between day 17 and 18 of gestation and after birth. Cultured fetal and early postnatal pituitary primordia were able to synthesize, to release and store the hormone, however, the pattern of these cellular functions varied according to the animal age when explantation was performed. Data derived from cultured pituitaries showed a gradual rise in the daily hormone content of the medium between fetal day 13 to 17. From fetal day 19 onwards, however, the daily discharge of LH decreased. These findings suggest that the fetal and early postnatal pituitary has the capacity to synthesize and release LH, furthermore after a period of independent differentiation hypothalamic signals appear to be required for pituitary hormone release.
D000818:Animals; D002454:Cell Differentiation; D046508:Culture Techniques; D005260:Female; D005865:Gestational Age; D007986:Luteinizing Hormone / Q000378:metabolism*; D010902:Pituitary Gland / Q000166:cytology*; D011247:Pregnancy; D011863:Radioimmunoassay; D051381:Rats
D007986:Luteinizing Hormone