Temperature and prolactin as control factors in newt forelimb regeneration

Abstract

Temperature and prolactin were studied as control factors i n the process of newt forelimb regeneration. Temperature was varied i n five steps from 10" to 30°C under otherwise constant environmental conditions. Longitudinal new growth and limb differentiation were observed. Temperature was found to have a profound effect upon both developmental processes. Maximal longitudinal new growth resulting from changes i n temperature alone occurred at 2 5°C with maximal limb differentiation a t 30°C. At each temperature studied, prolactin enhanced both new growth and limb differcntiation. With prolactin, maximum new growth also occurred at 25"C, but maximum limb differentiation occurred at 20°C. For our purposes optimum limb development was defined as the greatest new grow-th commensurate with full normal development. This optimum was reached by prolactin treated animals at 20°C when the regenerating limbs studied achieved 100% maximum normal differentiation and 87% maximum new growth. It was possible by employing a combination of temperature changes and hormone administration to control newt forelimb regeneration and produce a whole spectrum of limb development.

A staging system for the regeneration of a polyp from the aboral physa of the anthozoan Cnidarian Nematostella vectensis

“…Previous studies on Hydra (Peebles, ), planarians (Brøndsted and Brøndsted, ), fiddler crabs (Weis, ), and urodele amphibians (Schauble and Nentwig, ; Young et al, ; Tattersall et al, ) have also described a temperature‐based influence on the rate of regeneration. Similarly, the separation of regeneration into “wound healing” and “regenerating” phases was seen in newts (Schauble and Nentwig, ; Tattersall et al, ), salamanders (Bryant et al, ; Gardiner et al, ), and planarians (Brøndsted and Brøndsted, ); however, although the wound healing phase in newts also appeared to be temperature independent (Schauble and Nentwig, ; Tattersall et al, ), that of the planarians appeared to vary with temperature, although this is difficult to assess from the published data (Brøndsted and Brøndsted, ). Recent work in Nematostella has shown that, in bisection of juvenile polyps (5–10 mm in length), cell proliferation begins to increase roughly 24 hpa (at 22°C), reaching a maximum at roughly 48 hpa (Passamaneck and Martindale, ).…”

“…The two distinct phases of regeneration, the first being temperature independent (Stages 0-2) and the other being temperature dependent (Stages 2-5), suggest that the metabolic demands on wound closure are low, compared with the metabolically intensive morphological restructuring occurring at the later regeneration stages. Previous studies on Hydra (Peebles, 1898), planarians (Brïndsted and Brïndsted, 1961), fiddler crabs (Weis, 1976), and urodele amphibians (Schauble and Nentwig, 1974;Young et al, 1983;Tattersall et al, 2012) have also described a temperature-based influence on the rate of regeneration. Similarly, the separation of regeneration into "wound healing" and "regenerating" phases was seen in newts (Schauble and Nentwig, 1974;Tattersall et al, 2012), salamanders Gardiner et al, 2002), and planarians (Brïndsted and Brïndsted, 1961); however, although the wound healing phase in newts also appeared to be temperature independent (Schauble and Nentwig, 1974;Tattersall et al, 2012), that of the planarians appeared to vary with temperature, although this is difficult to assess from the published data (Brïndsted and Brïndsted, 1961).…”

Envirnmental conditions prerequisite for complete limb regeneration in the postmetamorphic adult land‐phase salamander, Ambystoma

“…Indeed, it has been shown that adult landphase forms will survive for only 2 to 3 months under conditions usually employed for studies on regeneration in aquatic forms (Scadding, 1977). Since studies pertaining to regeneration rates in newts have shown that the rates are greatly affected by adverse environmental conditions (Schauble, 1972;Schauble and Nentwig, 1974;Maier and Singer, 19771, it seems plausible that the reported inability of the adult land-phase salamander to regenerate a limb may be due to adverse laboratory conditions rather than actual loss of the intrinsic capacity to regenerate. The present study was initiated to determine what environmental conditions were necessary for long-term survival of adult land-phase Ambystoma salamanders in the laboratory and whether regeneration would occur in animals maintained under those conditions for prolonged periods.…”

Temperature Preference During Forelimb Regeneration in the Red‐Spotted Newt Notophthalmus Viridescens

“…Temperature alters rates of biochemical reactions in ectotherms in an exponential manner, affecting physiological functions such as metabolic rate, muscle activity, blood flow, digestion, and wound healing. Schauble and Nentwig (') observed that the rate of forelimb regeneration increased with increasing temperature, with low temperatures (10°C) effectively inhibiting regeneration. These findings are similar to thermal effects on limb regeneration in fiddler crabs (Weis, ').…”

“…These findings are similar to thermal effects on limb regeneration in fiddler crabs (Weis, '). Schauble and Nentwig (') also explored regeneration by examining both the rate of tissue growth as well as the rate of differentiation. Rate of growth measured the amount of new tissue produced from regenerating forelimbs over time, while the rate of differentiation measured the animal's limb morphology on a scale from 1 (wound healing) to 13 (completed differentiating).…”