194 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



rats with an ether-saturated isotonic acetate 

 buffer at pH 4.5 or 5. Prussian blue has been 

 added to the perfusion medium so that 

 the completeness of the perfusion can be 

 checked. Under these conditions the glyco- 

 protein of the granules of FSH cells was 

 almost entirely extracted whereas that of 

 the granules of LH cells was to a large ex- 

 tent retained. Assays showed that the buffer 

 extraction removed the FSH and some of 

 the LH; the extracted glands contained LH 

 without FSH. Barrnett, Ladman, McAllas- 

 ter and Siperstein (1956) obtained a similar 

 distinction between the granules of FSH 

 and LH cells by immersing hypophyses in 

 2.5 per cent trichloracetic acid. This treat- 

 ment removed most of the glycoprotein from 

 FSH cells and preserved the glycoprotein of 

 LH cells intact. Assays showed a loss of 

 FSH and a preservation of LH. 



I interpret these observations as indicat- 

 ing that basophil granules, like other secre- 

 tion granules, contain a mixture of proteins 

 and that the glycoproteins of LH-cell gran- 

 ules are less soluble than those of FSH- 

 cell granules. The loss of thyrotrophin and 

 FSH from whole rat hypophyses immersed 

 in 2.5 per cent trichloracetic acid must be 

 ascribed to inactivation rather than to com- 

 plete extraction, but it may well be that 

 the preservation of LH under these con- 

 ditions is related to its insolubility in 2.5 per 

 cent trichloracetic acid. It should not be in- 

 ferred however that all glycoproteins either 

 insoluble in, or rendered insoluble by tri- 

 chloracetic acid are LH. The conclusion of 

 Barrnett, Ladman, McAllaster and Siper- 

 stein that FSH often occurs in conjunction 

 with LH should be regarded as unproven. 



I. THE PARS ANTERIOR OF THE BAT WITH 



SPECIAL REFERENCE TO TWO TYPES 



OF GONADOTROPHS 



The pars anterior of the hypoi:)hysis of the 

 bat {Myotis '>nyotis) has been studied by 

 Hcrlant (1956a). Five types of cells are 

 distinguished by staining reactions. Two 

 are acidophils and three basophils. Aided by 

 the favorable staining properties of the cells 

 and by the unusual nature of the repro- 

 ductive cycle, Hcrlant has been able to 

 mak(> identifications of FSH cells and LH 

 ('(■Us in the bat that carry more conviction 

 than the id(nitifications made in tiie rat. 



The distinctive staining of the granules of 

 FSH cells and LH cells in the bat makes it 

 possible to assert that the two types are 

 quite separate, and do not change from one 

 type to another at different times. 



The two acidophil types in the bat are: 

 (1) Orangeophils. These are relatively sta- 

 ble throughout the reproductive cycle and 

 are presumed to secrete somatotrophin. (2) 

 Carminoi)hils. These are concentrated in the 

 anteromedian zone. They are in evidence at 

 the time of ovulation, become less prominent 

 towards the end of pregnancy and show in- 

 tense activity accompanied by a high con- 

 tent of cytoplasmic ribonucleic acid in ani- 

 mals that lactate after parturition. They are 

 considered to secrete prolactin. 



The three basophil types are: (1) Irregu- 

 larly shaped basophils scattered through the 

 par anterior, staining blue by trichrome 

 methods and with a marked affinity for 

 aldehyde-fuchsin. This type which is rela- 

 tively stable throughout the reproductive 

 cycle is provisionally identified as a thy- 

 rotroph. Its response to disturbances of 

 thyroid function has not been tested. 



(2) Basophils concentrated in the antero- 

 median zone, staining blue by trichrome 

 methods and with a slight aflfinity for alde- 

 hyde-fuchsin. These elements are large and 

 well granulated at the time of estrus in the 

 autumn and continue to show an active ap- 

 pearance throughout the period of hiberna- 

 tion when ripe follicles are in the ovaries. 

 They involute after ovulation in the spring 

 and remain involuted during pregnancy. 

 These cells are identified by Herlant as 

 FSH cells. 



(3) Basophils in the i)ostcrior two-thirds 

 of the pars anterior which show a marked 

 tendency to retain the red component of tri- 

 chrome staining methods and are therefore 

 violet or puri:)le but not blue after such pro- 

 cedures. They are brick-red in sections 

 stained by PAS and counterstained with 

 orange G, whereas the other two basophil 

 types which do not stain with orange G are 

 magenta. These cells are greatly hyper- 

 trophied through i)regnancy but undergo 

 |)rompt involution after parturition regard- 

 less of whether lactation follows. Herlant 

 identifies these cells as LH cells and this 

 identification is in accord with the marked 

 activity of LH cells during pregnancy in 



