Payette R F, Gershon M D, Nunez E A
Department of Anatomy and Cell Biology, College of Physicians and Surgeons of Columbia University, New York, New York 10032.
Anat Rec. 1987 Dec;219(4):394-401. doi: 10.1002/ar.1092190410.
The hypothesis that the secretory granules of mammalian gonadotrophs are heterogeneous was tested. Previous studies had shown that all of the granules contain beta-luteinizing hormone (beta-LH) immunoreactivity, and some contain beta-follicle stimulating hormone (beta-FSH) or 5-HT immunoreactivity. Moreover, differential release of beta-LH and beta-FSH has also been demonstrated. In the current study the pituitary glands of mice were investigated immunocytochemically at the ultrastructural level with antisera directed against human growth hormone (GH), beta-LH, beta-FSH, and 5-HT. The immunoreactivities of beta-LH, beta-FSH, and 5-HT were restricted to gonadotrophs. No 5-HT immunoreactivity was seen in somatotrophs, identified by the immunoreactivity of GH in the secretory granules of these cells. Antisera to beta-LH labeled all gonadotroph granules; however, anti-beta-FSH and anti-5-HT sera labeled only subsets of the granules. The proportion of granules labeled could not be increased by doubling the concentration of anti-beta-FSH serum. The incidence of double labeling of granules by antisera to beta-FSH and 5-HT was significantly less than that predicted from the incidence of granule labeling by either reagent alone. It is concluded that beta-FSH and 5-HT immunoreactivities do not co-exist in the same secretory granules of gonadotrophs; therefore, these granules are heterogeneous and there must be at least two types of granules. It is possible that the two types of granules may be responsive to different second messengers, thereby explaining the differential release of LH and FSH.
对哺乳动物促性腺激素细胞的分泌颗粒是异质性的这一假说进行了验证。先前的研究表明，所有颗粒都含有β-促黄体生成素（β-LH）免疫反应性，有些还含有β-促卵泡生成素（β-FSH）或5-羟色胺（5-HT）免疫反应性。此外，也已证实β-LH和β-FSH存在差异释放。在本研究中，利用针对人生长激素（GH）、β-LH、β-FSH和5-HT的抗血清，在超微结构水平对小鼠垂体进行了免疫细胞化学研究。β-LH、β-FSH和5-HT的免疫反应性仅限于促性腺激素细胞。在通过这些细胞分泌颗粒中的GH免疫反应性鉴定出的生长激素细胞中未观察到5-HT免疫反应性。β-LH抗血清标记了所有促性腺激素细胞颗粒；然而，抗β-FSH和抗5-HT血清仅标记了部分颗粒。将抗β-FSH血清浓度加倍并不能增加被标记颗粒的比例。β-FSH和5-HT抗血清对颗粒进行双重标记的发生率明显低于单独使用任何一种试剂对颗粒进行标记的发生率所预测的值。得出的结论是，β-FSH和5-HT免疫反应性不存在于促性腺激素细胞的同一分泌颗粒中；因此，这些颗粒是异质性的，并且至少存在两种类型的颗粒。这两种类型的颗粒可能对不同的第二信使有反应，从而解释了LH和FSH的差异释放。
