480 



PHYSIOLOGY OF GONADS 



roid drugs have no, or at the most rehi- 

 tively little, effect on the ovary. To these, 

 several additional reports should be men- 

 tioned. In thyroid-deficient female mice, 

 fertility and litter frequency were affected 

 only to the extent that the estrous cycles 

 were prolonged (Bruce and Sloviter, 1957). 

 In the rabbit, thyroidectomy did not inter- 

 I'upt or alter the periodicity of follicular 

 development, but it did eliminate the final 

 stages (Desaive, 1948). Parrott, Johnston 

 and Durl)in (1960) express the opinion that 

 the long i)hysiologic life of thyroid hormone 

 may account for many of the contradictions 

 in the reports of the relationship between 

 thyroid deficiency and reproduction. 



Except as it is speculative, an unex- 

 plained action of thyroidectomy or the ad- 

 ministration of goitrogenic drugs is the 

 augmentation of the ovarian response to 

 gonadotrophins and to anterior pituitary 

 im])lants (citations in Peterson, Webster, 

 Rayner and Young, 1952; and see in ad- 

 dition Janes, 1954; Janes and Bradbury, 

 1952; Kar and Sur, 1953). Thyroid sub- 

 stances, on the other hand, were inhibitory. 

 Of alternative hyjiotheses, Janes favored 

 the suggestion that during the period of 

 propylthiouracil treatment, provided it was 

 short rather than long, there was an ac- 

 cumulation of gonadotrophin in the blood 

 and the ovarian response varied for some 

 unknown reason according to the concentra- 

 tion of this latter substance in the body 

 fluids. To Kar and Sur (1953) direct in- 

 volvement of the hypophysis could be elimi- 

 nated; instead a direct role of the thyroid 

 seemed more plausible. They postulated 

 that the absence of thyroid hormone re- 

 duced the utilization of gonadotrophic hor- 

 mones by the ovary. 



The reported effects of the hyi)erthyroid 

 state or of administered thyroid hormone 

 on the ovary are equally conflicting. The 

 ovaries are described as being atrophic or 

 exhibiting incomplete folliculogenesis, or as 

 being essentially normal or even hyper- 

 trophied (citations in Peterson, Webster, 

 Rayner and Young, loc. cit., Hoar, Gov 

 and Young, loc. n't.). Irregular cycles are 

 said to have occuitcmI in the rat and mouse. 

 but no irregularity was detected in guinea 

 pigs given thyroxine. 



A tentative explanation can be given for 



the many divergent reports of the relation- 

 ship between the thyroid and the ovary, 

 divergencies which are found in the clinical 

 literature as well as in laboratory studies. 

 In doing so, we will recall that there is 

 abundant evidence that the ovary is a locus 

 of action of thyroid hormone. The action 

 may not be directly trophic, as is that of 

 the pituitary, but it is assumed to be su])- 

 l)ortive, jiossil)ly directly so. or jiossiljly 

 indirectly through regulation of the general 

 metabolic level. Whatever its nature, there 

 must be great interspecies and even intra- 

 species variation in the need of the ovary 

 for such action. In addition, within a species 

 there appears to be a wide range of toler- 

 ance, for Peterson, Webster, Rayner and 

 Young (1952) found in their study, in 

 which the thyroid state was estimated from 

 measurements of oxygen consumption and 

 heart rate, that reproduction occurred in fe- 

 males in which oxygen consumption ranged 

 from an average of 50.0 to 93.5 cc. per 100 

 gr. i)er hr. (52.9 in the controls), and heait 

 rate from 238 to 316 beats per minute (272 

 in the controls). In females that failed to 

 rejiroduce, the lowest values were lower 

 than in the animals which did reproduce; 

 nevertheless, there was much overlai)i)ing, 

 for in this group oxygen consumption ranged 

 from an average of 46.7 to 94.1 cc. per 100 gr. 

 l)er hr., and heart rate from 202 to 330 beats 

 j)er minute. Within sucli a framework, there 

 are bound to be more divergent results 

 than when normal functioning depends on 

 nioi'e narrowly circumscribed conditions, 

 and the failure to replicate a result does 

 not have the same significance. As a part 

 of the investigation of sucli a problem, more 

 and better correlated infoi'niation is re- 

 (|uiicd, and this could be the most pressing 

 ne('(l in the field of oxarian (and icproduc- 

 ti\-cl functioning and the thAM'oid. 



B. ADRENAL CORTEX 



Tlu^ adrenal cortex elaborates its steroid 

 )nn()iu's in a biosyiU lictic scciuencc \H'ry 



siiiiilai' to that in the o\aiy. In fact, i)ro- 

 gcstci'onc is an intermediate substance in 

 the synthesis of glucocorticoids. Estrogen 

 has been found in extracts of adrenal corti- 

 cal tissue, but whether it represents a deg- 

 radation pi'oduct within the adrenal or an 

 artifact resulting from the chemical i)i'o- 



