Reptiles glands

A microsomal O -methyltransI erase that methylates a number of alkyl-, methoxy-, and halophenols has been described from rabbit liver and lungs. These methylations are inhibited by SKF-525, A-ethyl-maleimide and /->-chloromercuribenzoate. A hydroxyin-dole O-methyItransferase, which methylates A -acetyl-serotonin to melatonin and, to a lesser extent, other 5-hydroxyindoles and 5,6-dihydroxyindoles, has been described from the pineal gland of mammals, birds, reptiles, amphibians, and fish. 

Some parts of the brain, like the cerebral cortex, are much more highly evolved in humans than in other animals. The pineal gland, however, is a very basic organ that first evolved in primitive species. It is found in lampreys, fish, amphibians, and reptiles, as well as in mammals. The hormone melatonin has also been found in insects and plants. 

Pineal gland A tiny, light-sensitive organ in the center of the brain, also called the pineal eye or "third eye." In reptiles it controls changes in skin color. In humans it is a master gland of the endocrine system, probably regulating many biorhythms. 

Like marine reptiles, marine birds have glands that remove excess salt from their bodies. Although the structure and purpose of the salt gland is the same in all marine birds, its location varies by species. In most marine birds, salt accumulates in a gland near the nostrils and then oozes out of the bird s body through the nasal openings. 

The lymphoid system of the amphibians is more complex than that of fishes. In addition to a well-defined thymus gland, primitive lymph node tissue is also present (Kent et al., 1964). In frogs and toads for the first time marked seasonal changes in thymic size are noted (Dustin, 1911). Reptiles have a lymphoid system that is quite similar to that seen in amphibians, including a well-developed thymus that also involutes with age (Dustin, 1911). 

Chieffi, G., Chieffi-Baccari, G., Di Matteo, L., d Istria, M., Marmorino, C., Minucci, S., and Varriale, B., 1992, The harderian gland of amphibians and reptiles, in Harderian Glands Porphyrin Metabolism, Behavioral and Endocrine Effects, S.M. Webb, R.A. Hoffman, M.L. Puig-Domingo, and R.J. Reiter, eds.. Springer Verlag, Berlin, pp. 91-108. 

Saint-Girons, H., 1988, Les glandes cephaliques exocrines des reptiles I - Donnees anatomiques et histologiques, Ann. Scl Nal Zool Paris, I3e serie 9 221-255. 

Prompted by curiosity, Katsoyannis and du Vigneaud synthetized [80] in 1958, a peptide with the ring of oxytocin and the side chain of vasopressin. The hybrid molecule, vasotocin, had the biological properties of both parent hormones. Soon after its synthesis the peptide was detected in extracts from the pituitary glands of birds and reptiles and later in the pineal gland of mammals, including man. 

I feel that it is preferable to use the term semiochemical as defined in Albone (1984). My caution in this matter is predicated by two major factors. First, for none of the "skin glands" in amphibians and reptiles to which I shall refer is there a sufficient body of data to state categorically that this signal produced by this source has this significance (Albone, 1984 fig. 2.1 and accompanying text). Second, some anatomists might question whether many of the reptilian structures should be properly termed "glands." This caveat is so fundamental that it deserves further explication. 

Wright, D. E., and Moffat, L. A., 1985, Morphology and ultrastructure of the chin and cloacal glands of juvenile Crocodylus porosus (Reptilia, Crocidilia), "Biology of Australian Frogs and Reptiles," R. Shine, G. Grigg, and M. Ehrman, eds., in press. 

Pineal gland, pineal body, epiphysis, Corpus pine-ale a small, cone-shaped, unpaired organ situated between the cerebral hemispheres on the roof of the third ventricle of the mammalian brain. Phylogeneti-cally, the P.g. is a vestigial parietal eye, the light sensitive organ of reptiles. It produces the hormone Melatonin (see). 

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