Thyroid hormone resistance (THR) is a rare syndrome of reduced end organ sensitivity. Patients with THR have elevated serum free thyroxine (FT4), free triiodothyronine (FT3), but normal or slightly elevated serum thyrotropin values. The characteristic clinical feature is goitre without symptoms and metabolic consequences of thyroid hormone excess. THR can be classified on the basis of tissue resistance into pituitary, peripheral or generalised (both pituitary and peripheral) types. Mutations in the TRbeta gene, cell membrane transporter and genes controlling intracellular metabolism of thyroid hormone have been implicated. THR is differentiated from thyroid stimulating hormone (TSH) secreting pituitary adenoma by history of THR in the family. No specific treatment is often required for THR; patients with features of hypo- or hyperthyroidism are appropriately treated with levo-triiodothyronine (L-T3), levo-thyroxine (L-T4), dextro-thyroxine(D-T4) or 3,3,5 triiodo-thyroacetic acid (TRIAC). The diagnosis helps in appropriate genetic counselling of the family.

The topographical distribution of enkephalin in the central nervous system of the lizard, Anolis carolinensis, has been studied by the immunoperoxidase technique with antiserum to leucine-enkephalin. Immunoreactive enkephalin perikarya, fibers and probably terminals are widely distributed throughout the central nervous system, which agrees well with the distribution of enkephalins in the mammalian brain. Enkephalin-containing perikarya are found in the subpallium (septum, nucleus accumbens, striatum, amydgala), preoptic and hypothalamic region, ventromedial nucleus and ventromedial area of thalamus, pretectal geniculate nucleus and posterodorsal nucleus of pretectum, nucleus of the lateral lemniscus, locus ceruleus, spinal trigeminal nucleus, nucleus of the solitary tract, medial parvocellular nucleus, and dorsal horn of the spinal cord. Enkephalinergic fibers and terminals are found in the above-mentioned areas as well as in the pallium (medial and dorsal cortex, dorsal ventricular ridge), dorsomedial and anterior dorsolateral nucleus of the thalamus, habenula, nucleus of the stria medullaris, torus semicircularis, mesencephalic tegmental area, interpeduncular nucleus, mesencephalic trigeminal nucleus, central gray, reticular formation, raphe nucleus, substantia nigra, isthmus region, and nucleus of the trapezoid body. Enkephalinergic pathways appear to exist between the septum and the medial cortex, nucleus accumbens and nucleus of the lateral olfactory tract, striatum and certain mesencephalic structures, hypothalamus and tegmentum, and between nucleus of the lateral lemniscus and torus semicircularis. In the pituitary, cells of the pars intermedia, and certain cells of the rostral pars distalis also show immunoreactivity to enkephalin antiserum. The distribution of enkephalin immunoreactivity throughout the hypothalamus and in the median eminence suggests involvement in neuroendocrine regulation. Presence of enkephalin in many extrahypothalamic brain areas indicates its important role in various sensory functions and in behavioral and autonomic integration.

The pituitary gland of the musk shrew, Suncus murinus L. was studied with special reference to the cytology of the adenohypophysis. In addition to the agranular cells (chromophobes ), seven morphologically and tinctorially distinct Nchromophilic cell types (four mucoid and three acidophilic) were observed in the pars anterior. These cells have been tentatively named as types one to seven. On the basis of their morphology, topography and staining reactions, cells of types one to six were compared, respectively, with the TSH, FSH, ICSH (L,H), LTH (prolactin), STH and ACTH cells of other mammals. The identity of type 7 cells could not be determined. Although mucoid cells (types 1, 2) art: more concentrated in the rostroventral region of the pars anterior, a definite "zona tuberalis" seems to be lacking. Since the musk shrew is not a seasonal breeder, the gonadotropic cells (types 2, 3 ) of the adenohypophysis do not seem to fluctuate in structure during the different times of the year. However, conspicuous hypertrophy, hyperplasia and intense secretory activity of type 4 cells during pregnancy and lactation reinforces the postulation that these cells are lactotropic in function. Follicular cysts and colloid in the residual cleft were observed in a few instances. Their possible origin and significance are discussed.Knowledge cif the morphology and cytology of the hypophysis in several groups of mammals has been enriched immensely i n recent years. (Purves, '61, '66; Herlant, '64, '65; Hansi:rom, '66; Girod, '66; Allanson and Parkes, '66). However, only scanty inform ation is available on the order Insectivora, except for the mole (Herlant, '64; Holmes, '66), desman (Herlant, '64) and hedgehog (e.g., Girod et al., '66, '67). The family Soricidae of this order does not seem to have received any attention, the (only study having been confined to brief description of the hypophysis of the short-tailed shrew, Blarina (Dawson, '63; Hanstrom, '66). The present paper presents a detailed anatomical description of the hypophysis and a comprehensive account on the cytology of the adenohypophysis of the musk shrew, Suncus ,murinus L. Banaras Hindu University c a m m s and adjacent areas were used. Included were 50 females in different stages of gestation, 12 pregnant and concurrently lactating females, 8 lactating females, 90 non-pregnant females and nearly 100 males. Most of the animals were sacrificed within 12 hours of capture; some were maintained in the laboratory for varying periods before sacrifice. Conspicuous seminiferous tubules visible through the tunica albuginea of the testes, and the presence of spermatozoa in the testes and the genital tract, were taken as indicators of sexual maturity in the male. Since some animals weighing 28-35 gm were pregnant, females weighing 40 gm or more were regarded as being sexually mature. The condition of the mammary glands, uteri and ovaries were considered in assessing the sexual maturity of the female. Pregnant females were classified into three groups (those of early, ...

Immunocharacteristics of the pars distalis cells of the pituitary of the male lizard A. carolinensis are determined by employing the immunoperoxidase technique with antisera to mammalian pituitary hormones. On the basis of their immunoreactivity, 5 different cell types with characteristic anatomical distribution are recognized. ACTH cells are found in the rostral half of the pars distalis, and PRL cells in the rostral two thirds of the pars distalis. GH and TSH cells are located in the caudal half of the pars distalis. GTH cells are distributed throughout the gland. When consecutive sections are stained with antiserum to ovine FSH or its beta-subunit and to ovine LH, the same cells show immunoreactivity to all the three antisera. None of the GTH cells show positive immunoreactivity to ovine beta-LH antiserum. The results suggest the existence of one gonadotropic cell type in the pituitary of this lizard.