Seasonal variations in the nyctohemeral rhythm of plasma testosterone in the European badger Meles meles L

In the badger a seasonal sexual rhythm of the plasma testosterone is observed. There is also a nycthemeral rhythm of the testosterone secretion; during the regressed period of the testis this rhythm is bimodal with testosterone peaks during the light phase of the day; during the active period and "activity rhythm" with many transitorys peaks during the dark phase is added.     

Morphogenesis and hormonogenesis in vitro of granulosa cells of the European badger Meles meles L.]

Granulosa cells harvested from follicles of Badger during inactive luteal phaseluteinize in vitro. The results demonstrate that the serum's origin influence progesteron production of Badger's granulosa cells in culture. LH appears equally to be stimulating.     

Seasonal variations in the blood testosterone and thyroxine levels in the hedgehob (Erinaceus europaceus L)]

In adult male European Hedgehogs, which were studied outdoors, the plasma levels of both testosterone and thyroxine exhibited a marked annual cycle with a minimum in autumn and a maximum during spring and summer. The winter resumption of the testicular activity started already during the phase of hibernation and was concomitant with an increase of the plasma thyroxine level. The plasma titers of the two hormones dropped down together in August. The correlation between both hormones was less close from May through July.     

Cutaneous respiration in a Selachian (Scyliorhinus caniculus L.)]

Cutaneous oxygen consumption (Mo2) and cutaneous oxygen uptake from the external medium were investigated in an elasmobranch Scyliorhinus caniculus L. In spite of an important Mo2 (2.75 +/- 0.28 nmol.mn-1 cm-2 ; n=6) a positive net flux of oxygen through the skin takes place (2.98 +/- 0.33 nmol. mn-1 .cm-2). The skin of the dogfish in an exchanger for oxygen supplying 10% of oxygen requirements of other organs of the body in these experimental conditions (t = 13 degrees C).     

Seasonal variations in the sexual activity of the male genet (Genetta genetta L.)]

The Genet testis shows a spermatogenic activity throughout the year. The plasmatic androgen level presents two periods where the values are higher; one in spring the other in autumn. The spring testosterone rise co?ncides with a mating period.     

Suppression of annual plasma testosterone and thyroxine cycles in the edible dormouseGlis glis under constant photoperiod at 24°C

Summary Exposure of male ebible dormice all year round to an unwarying photoperiod and warm temperature disrupted their biological cycles; hibernation was almost completely suppressed, and short lived infradian cycles of body weight, and of plasma testosterone and thyroxine were measured instead of the normal annual patten.     

Effects of injections of ecdysterone on the molt and regeneration in the crab Carcinus maenas (L.)]

Two successives injections of 10 microng/g of ecdysterone induce precocious ecdysis in 66% of Crabs. This induction of precocious ecdysis is always accompanied by an inhibiting effect on regeneration: tiny abnormal regenerates or none are obtained. A majority of recipients of ecdysterone underwent successful ecdysis. Experimental results are discussed; a morphological and cytological study of ecdysterone effects on regeneration is announced.     

Suppression of annual plasma testosterone and thyroxine cycles in the edible dormouse Glis glis under constant photoperiod at 24 degrees C

Exposure of male edible dormice all year round to an unvarying photoperiod and warm temperature disrupted their biological cycles; hibernation was almost completely suppressed, and short lived infradian cycles of body weight, and of plasma testosterone and thyroxine were measured instead of the normal annual pattern.     

Inhibition of corticotropic function by administration of GABA in carp (Cyprinus carpio L.)]

The intracardiac injection (50 microgram/g) of GABA to Carps clearly inhibits the rise of the plasma cortisol level which occurs usually in response to the blood sampling manipulations. The inhibition starts thirty minutes after injection and lasts till the end of the experiment two hours later. The hypothesis that this neurotransmitter has a regulatory function on the corticotrop cells, especially on the excretion of ACTH has to be considered.     

Autoradiographic analysis of the primary visual projections of a diurnal predator (Buteo buteo L.)]

Radioautographic analysis of the optic system of a Common Buzzard (Buteo buteo L.) show hypothalamic (Meier's areas 1, 2 and 3), thalamic (nuclei lateralis anterior, geniculatus lateralis ventralis, dorsolateralis anterior), pretactal (nuclei geniculatus lateralis pretectalis--or Kuhlenbeck's geniculatus lateralis dorsalis--superficialis synencephali, griseus tectalis and area pretectalis), tegmental (nucleus ectomammillaris) and tectal visual projections. A general survey of Common Buzzard optic structures suggest a certain preponderancy of tectofugal system on thalamofugal system. Centrifugal visual system is reduced.