THE INDUCTION OF OVULATION IN THE 



HUMAN BY HUMAN PITUITARY 



GONADOTROPIN 



Carl A. Gemzell 



Department of Obstetrics and Gynecology, Karolinska Hospital 

 and King Giislaf Vs Research Institute, Sweden 



The clinical effects of gonadotropins, both pituitary gonadotropins and those 

 obtained from extra-pituitary sources, such as pregnant mare serum or urine 

 from pregnant, castrated or menopausal women, have been disappointing. 

 In some cases, a polycystic enlargement of the ovaries has been reported but 

 the finding is inconsistent. It is questionable whether the follicular growth 

 induced results in maturation of an ovum to the graafian stage of development 

 or whether an ovulation takes place when the luteinizing factor is added. 

 The small number of pregnancies reported following such treatments indicates 

 that an ovulation is brought about only occasionally or independently of 

 the treatment. 



The reason for the negative clinical results may be sought in the fact 

 that gonadotropins obtained from other species have been used. Witschi (I) 

 has shown that species specificity exists between gonadotropins of mammalian 

 and amphibian origin and similar results in monkeys have been reported by 

 Simpson and van Wagenen (2). An FSH preparation isolated from monkey 

 pituitaries produced repeated ovulations in the monkey whereas FSH from 

 sheep or pig pituitaries was less active. A similar specificity exists for other 

 pituitary hormones such as growth hormone (GH). Li and Papkoff (3) have 

 suggested that differences in biological activity result from differences in 

 chemical structure. Human GH, for example, has a smaller molecular weight, 

 an isoelectric point more on the acid side and different amino-acid end-groups 

 than GH obtained from bovine pituitaries. 



Antigonadotropic factors may also be the cause of the negative results. 

 It has been noticed for a long time that the ovarian response to continued 

 injections of gonadotropins gradually diminishes. Pregnant mare serum 

 gonadotropins and those from sheep or pig pituitaries cause the appearance 

 of antigonadotropic substances in blood as early as four weeks after the 

 beginning of the treatment. Human chorionic gonadotropin or gonadotropin 

 from the urine of castrated or menopausal women, however, does not give 

 rise to antihormone formation, apparently because of its homologous origin. 



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